The present invention relates to a magnetic image detection device which measures magnetic distribution (magnetic image) in a first or second dimension.
Measurement of magnetic distribution is widely used in the development of devices which utilize a magnetic field, for example, electron beam polarizers, electron beam focusing devices, motors, developing units in copying machines, etc.
It would furthermore be extremely advantageous if the inspection and analysis of reinforcing rods in concrete blocks and other internal structural members could be performed by means of nondestructive tests using the measurement of magnetic distribution. In addition, it would also be extremely beneficial for the medical sciences if the distribution in one or two dimensions of minute magnetic fields emitted from the brain or heart could be measured.
Conventionally, the measurement of magnetic distribution in one or two dimensions has been accomplished as described below. Specifically, magnetic distribution has been obtained by mechanically moving a Hall element or other magnetic sensor and sequentially plotting the magnetic field intensity obtained by the magnetic sensor at each detection position.
Thus, because when measuring the magnetic distribution in one or two dimensions with a conventional device magnetic sensors are mechanically moved, the magnetic intensity occurring at each position is measured, and the magnetic field intensity obtained at each position is sequentially plotted as previously described, precision is low and much time is required for measurements. Additionally, it is not possible to measure magnetic distribution over time, specifically magnetic distribution in motion.
It is possible to align multiple Hall elements in order to correct the problems of low measurement precision and the long measurement time requirements. However, there is a limit to the density in which Hall elements can be arrayed, and high density array devices cannot be used. Moreover, because sensitivity of a Hall element is low, the magnetic distribution of weak magnetic fields cannot be detected.